When seamless pipe production by hot rolling is carried out by Mannesmann process, it is well-known that seizing flaw called “shoe mark” is produced on the surface of seamless pipe during piercing-rolling process of a seamless pipe using a piercing-rolling mill because of the contact between the material for seamless pipe (hereinafter, it may be referred to “pipe material”.) and guide shoes of the piercing-rolling mill.
In order to solve this problem, for example, Patent document 1 discloses a piercing-rolling method where a mixed liquid type coating material (which is provided by adding sodium silicate (water glass) as a binder to metal oxide particles such as iron oxide) is applied onto the circumferential surface of guide shoes. In addition, Patent document 2 discloses lubricants for hot process composed of an aqueous solution containing an iron oxide, a sodium silicate, a starch, and a xanthan gum.
Moreover, Patent document 3 discloses a hot-rolling method to form a coating onto guide shoes and so on by applying a coat-forming solution mainly containing aqueous polymer salt prepared by non-aqueous polymeric acid and a coat-forming supplementary solution containing strong acid or aluminum salt thereof as the main component to make coating component in the polymer salt deposit from the coat-forming solution.
Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 60-21111
Patent Document 2: JP-A No. 11-35967
Patent Document 3: JP-A No. 4-288916